An afterglow is a broad high arch of whitish or rosy light appearing in the sky due to very fine particles of dust suspended in the high regions of the atmosphere. An afterglow may appear above the highest clouds in the hour of deepening twilight, or reflected from the high snowfields in mountain regions long after sunset. The particles produce a scattering effect upon the component parts of white light.
After the eruption of the volcano Krakatoa in 1883, a remarkable series of red sunsets appeared all over the world. These were due to an enormous amount of exceedingly fine dust blown to a great height by the volcano's explosion, and then globally diffused by the high atmospheric currents. Edvard Munch's painting The Scream possibly depicts an afterglow during this period.